PetroStreet

1)What is WRC ?

2)Whats the difference between WRC 297 and WRC 107?

3) what is the meaning of the term "local nozzle flexibilities"?

1. Welding Research Council is a dedicated organization which is performing research in the field of welding for various applications. Like it owns PVRC (Pressure Vessel Research Council) against which it has released several documents like WRC-107 and WRC-297. WRC provides actual technological developments upon performing actual research work with much of investment.

2. Both deal with the stress at nozzles on pressure vessels due to external loadings. WRC-107 is the earlier bulletin however WRC-297 is the revision of WRC-107. I have a technical paper regarding the same. Will look for you as that mentions some clear differences between the two. Both these were used in earlier days to estimate the effect of nozzle loadings manually but now these are directly loaded in the softwares which handle these.

3. Nozzle to shell flexibility is the measure of stiffness of nozzle member at the shell junction. This can be estimated using WRC-297 or using computer aided designs. Many softwares are available which can perform this check and provide the appropriate element length after calculating spring rates.

Hello again. I have attached the technical paper I was referring to. It's an old one but worth reading.

Thanks Mechcolor. Good document indeed.

There comes differences in calculations made by WRC-107 and then with WRC-297 as their strategy differs but following WRC-297 for cylindrical shells is the appropriate way as it is a supplement to WRC-107. However, it should also be kept in mind that WRC-297 does not have any provisions for spherical vessels. In that case, WRC-107 would govern.

For Local nozzle flexibility , is this statement correct , "Every vessel nozzle has some flexibility , during thermal growth , nozzle can deform towards vessel or towards piping to which this nozzle is attached . the stiffness of that flexibility is calculated by WRC 297"..?

Yes the statement is correct but the loadings may not be of thermal nature. There are three steps in estimating the nozzle flexibility.
1. Calculate the stresses due to loading (external loading due to connected piping)
2. Calculation of stress intensity factors due to combined load.
3. Comparison of calculated stress as if they are in allowable limits as allowed by applicable design code
If the stresses are well within the limit of allowable stresses as per design code, nozzle flexibility will pass. I would refer you to Appendix A of WRC-297 which guides you through the whole calculation sequence.
For higher D/T vessels, nozzles are very flexible, same is the case for d/t of nozzle.

Note: WRC-297 in addition to WRC-107 provides you with the details of stress calculations in the nozzle at the juncture with the vessel. WRC-297 also covers larger D/T ratios of vessels than WRC-107.

Can i get E-copy of the bulletins of WRC 107 and WRC 297?

Regards

Copyright material.
If you want to know about any thing specific out of them, you may ask.

Can you please elaborate the scope of both WRC 107 and WRC 297 in a bit detail ? Thanks

Regards